The new standard

IO-Link Safety

Safe communication from start to finish
IO-Link logo

What is IO-Link?

IO-Link is the first globally standardized I/O interface. The technology has established itself as the communication standard in machine building and systems manufacturing. The number of products with IO-Link interface used is growing rapidly. The communication standard offers you many advantages, creates new application opportunities, and constitutes an investment in important matters such as the Industrial Internet of Things (IIoT). By definition, IO-Link is an open, serial point-to-point communication protocol for connecting sensors and actuators to an automation system.

Your advantages

  • IO-Link increases productivity
  • IO-Link simplifies installation, maintenance, and replacement processes
  • IO-Link increases data availability and accuracy
  • IO-Link enables troubleshooting via remote diagnostics
Signal light in production


IO-Link devices provide the controller with detailed condition data. This data aids maintenance planning because you can identify problems quickly. If you, as a user, receive a warning message from dirty sensors every six months, for example, you can arrange for them to be cleaned twice a year at a convenient time. Furthermore, real-time fault detection of devices enables you to reduce operating costs by minimizing unplanned downtimes.

Installation in the control cabinet


Everything in IO-Link is easy. Installation is easy because you can use standard cables and connectors. Maintenance is easy because you can monitor your systems and modify the settings. Using the error detection feature of IO-Link devices, you can determine the cause of a problem quickly and easily. The replacement process is also easy because the parameter data is stored in the controller. If an IO-Link device needs to be replaced, the stored parameters are automatically copied to the IO-Link device without using a programming device. As a result, your system is quickly ready to operate again.

Data analysis on screen

Increased data availability and accuracy

Analog sensors without IO-Link often pass through multiple A/D conversions before data reaches the controller, which may result in errors. In IO-Link devices, there is only one A/D conversion. This increases measuring accuracy and thus the accuracy of the entire process.

Remote configuration on a PC

Remote configuration

You can modify the parameters of the IO-Link device from your desk by responding to status messages. You therefore no longer have to shut down the production line and physically access the devices in order to rectify faults.

IO-Link Safety

IO-Link Safety implements safe communication from start to finish. This means that users also benefit from typical IO-Link advantages in the field of functional safety, such as simple parameterization with IODD or fast device replacement.

The extension of the IO-Link technology enables consistent communication from the control level right through to the connection of safety-related sensors and actuators. The interaction of IO-Link and IO-Link Safety promises new, manufacturer-independent machine and system concepts.

Components of an IO-Link system

The architecture of an IO-Link system consists of a controller, an IO-Link master, and one or more IO-Link devices. They are connected by simple 3-wire, unshielded cables, which makes installation easier and more cost-effective.

Interactive image map: Components of an IO-Link system
IO-Link master
The master provides the interface to the higher-level controller, controls communication with the connected IO-Link devices, and stores parameter data and the IODD (IO Device Description) file. This file contains a device description and parameter information regarding the IO-Link device, including the manufacturer, item number, function, etc.
PLC (programmable logic controller)
The controller is used to monitor the state of the inputs and control the state of the outputs. A safety controller is required in order to process safety data.
IO-Link devices
This term refers to all intelligent sensors or actuators connected to the system such as I/Os, converters, safety relays, motor starters, or device circuit breakers. With regard to IO-Link, “intelligent” means that a device has identification data, e.g., a type designation, serial number, or parameter data. This data can be read via the IO-Link protocol. In addition, the IO-Link device can supply detailed diagnostic data that can be used for preventive maintenance and servicing.
An actuator is an output device that converts electric signals and current into mechanical movement and thus controls mechanical installations.
A sensor is a device that measures a physical variable (e.g., temperature, pressure, or position) and records and displays the values or provides feedback.
IO-Link Safety master
In addition to performing the tasks of a classic IO-Link master, the IO-Link Safety master enables safe communication in the field of functional safety. In addition to classic standard IO-Link devices, safety-related IO-Link devices can be connected here, such as safety sensors, safe sensors via OSSDs, safe actuators, or even mixed safety devices (e.g., mechatronic devices).

What can an IO-Link device do that a standard sensor cannot?

IO-Link devices supply three types of data:

  • Process data: Condition information that the IO-Link device reads and sends to the IO-Link master or information that the IO-Link master sends to the IO-Link device. Status information is also transmitted in this process. You can thus check whether the process data is valid. An example of process data is the distance measured by a distance sensor.

  • Service data: Information that can be written to the IO-Link device or read from the IO-Link device. Example: The model or manufacturer number of the sensor, which can be used to identify a device or configure a new one.

  • Event data: Notifications such as error messages, which are sent from the IO-Link device to the IO-Link master as soon as the event occurs, e.g., overheating.

IO-Link products

IO-Link masters and devices for the control cabinet and for field installation

IO-Link products

Our product portfolio for communication from start to finish:

  • IO-Link Safety master and device
  • IO-Link masters for IP20 and IP67
  • Safe and standard I/O boxes
  • Analog converters
  • Safety relays
  • Hybrid motor starters
  • Device circuit breakers
  • Power supplies